Monday, January 08, 2007

Everyone has heard of dark matter, the stuff that makes up 25% of our universe. No one yet knows what it is, but its presence can be measured by the effects of its mass on visible matter. It apparently emits no radiation, nor does it reflect any. It is not merely dark, however. It cannot be seen by its blocking light from other sources. It is completely invisible. And yet it exerts a gravitational pull on normal matter such that it is theorized to be a kind of scaffolding, or skeleton, upon which stars and galaxies formed.

For the first time ever, using gravitational lensing (whereby light coming from the distant reaches of space can be seen to bend as it passes filaments of dark matter, as if through a lens), cosmologists have been able to map the structure of dark matter concentrated in filaments throughout the universe. According to news@nature.com,

"The map shows that, as predicted, the mysterious dark matter that makes up a quarter of the Universe forms a filamentous 'skeleton' upon which visible matter congregates, eventually producing stars. This is the first time such a large-scale three-dimensional picture of dark matter has been produced, and it will allow cosmologists to probe deeper into the nature of this elusive matter."